As early results come in, Clinton leads 58.7% to Sanders 41.3%.
Democratic primary races are also being held in California, Montana, New Mexico, and South Dakota. North Dakota is holding a caucus. The final primary will be held in Washington DC next Tuesday.
This race comes one day after the Associated Press announced that the former first lady has earned enough delegates to clinch the Democratic presidential primary nomination. That announcement was based partially on a survey of superdelegates.
In California, Clinton is hoping for a substantive victory that could better position her to rally Democratic voters around her candidacy after a bitter primary.
Clinton’s opponent, Vermont Senator Bernie Sanders, has indicated that he plans to remain in the race until the convention in July, hoping to win over superdelegates.